ENGLAND manager Sven-Goran Eriksson admitted his side needed to improve.

But the Swede said he was still satisfied with England's performance as they defeated Paraguay in Frankfurt, thanks to Carlos Gamarra's own goal.

Asked whether England might perform better against Trinidad and Tobago in four days time Eriksson said: "I hope so. You always try to do better, but I'm happy. We started the tournament with three points and it's very important."

The sizzling German heat appeared to take a heavy toll on England's players, and Paraguay coped better and looked fitter than Eriksson's men in the latter stages of a tense match.

"Maybe we suffered a lot," said Eriksson.

"I think this was a real hot, hot day and that knocked us in the second half."

Eriksson said his much-criticised decision to take Michael Owen off early in the second half - replacing him with Middlesbrough winger Stewart Downing - was purely tactical.

Following the switch, Chelsea midfielder Joe Cole occupied a role just behind Peter Crouch, with Downing playing on the left.

"I thought we were finding it difficult to keep the ball, so I tried to have a player who could link the ball up a little," said Eriksson.

He rejected the suggestion that replacing Owen caused England's performance to fade.

England skipper David Beckham also blamed the heat for his team's lacklustre performance: "We found it difficult, but we will get better in the next match and it was important to open with three points."